It is important to treat crop plants and turf (such as golf course and grassy public park areas) with pesticides and/or other crop protection agents in order to control pest-induced damage to the crops or turf. For grower and/or public acceptance, the treatments ideally should leave no negative odor, or at most only a mild odor which is not considered to be negative, unpleasant or repulsive to humans.
One of the most well-established classes of insecticides is the organophosphates, with organothiophosphates and organodithiophosphates making up a significant subclass. For the purposes of the present invention the term “organothiophosphate” is meant to also include organodithiophosphates. The latter compounds are highly active, relatively safe and relatively inexpensive, providing an economic means of controlling insect pests. One of the most commercially important compounds in this class is acephate. Acephate, like other organothiophosphates, can leave an unpleasant, objectionable odor in the treated field. This negative odor can introduce restrictions on the times when the composition can be applied in areas frequented by members of the public. Such negative odors can also reduce grower acceptance of the product.
Previous attempts to produce odor-reduced formulations of organothiophosphates have focused on the addition of odor-masking agents, such as perfumes and volatile essential oils. Thus, acephate has been formulated with odor-masking agents to provide compositions in which the objectionable odors from the active ingredient have been masked at least to some degree (see U.S. Pat. No. 7,407,927, the entire contents of which are incorporated herein by reference).
There continues to be a need for more effective odor control in the formulations of organothiophosphates as well as combinations of organothiophosphates with other crop protection agents. Effective odor control also must not compromise the efficacy of the active ingredient(s), or the storage stability of the composition. The present invention is directed to meeting this need.